Please tell me how to proceed with a lawsuit for the return of unjust enrichment.

I understand that you have inquired about how to proceed with a lawsuit for the return of unjust enrichment.

As in the situation you asked about, if you wish to get back an amount that was unjustly transferred due to a mistaken transfer, you can recover that amount through a lawsuit for the return of unjust enrichment.

Unjust enrichment refers to a benefit that arises when a person unlawfully acquires another's property.

A mistaken transfer is a monetary benefit arising from an unintended transaction, so the person who received the transfer has an obligation to return it.

Before proceeding with a lawsuit for the return of unjust enrichment, you should first request the other party to return the amount that was mistakenly transferred.

You said you have already made a request, but it appears that you are in a situation where you cannot reach them.

In this case, you may also consider sending a certified letter of content.

This is because a certified letter of content puts legal pressure on the other party and can be used as favorable evidence in subsequent legal proceedings.

If the other party refuses to return it or cannot be reached, you can file a lawsuit for the return of unjust enrichment.

In order to proceed with the lawsuit, you must prepare evidence such as the transfer receipt, the account number, and the account transfer records.

Through this, the court can recognize that the transfer occurred by mistake and order the other party to return it.

However, if the other party does not return the amount or if return is impossible, additional legal procedures may be necessary.

In this case, the court can impose not only the return of the amount but also interest on the amount that has not been returned.

Through these procedures, you can recover the amount that was unjustly transferred, and it is advisable to seek the help of an attorney specializing in civil matters before the lawsuit.